1. Field of the Invention
The present invention relates to a subscriber profile changing method, a subscriber profile file updating method, a mobile communication system, an Exchange, and a home memory station.
2. Description of the Related Art
FIG. 1 is a diagram illustrating a communication method of downloading a subscriber profile into an exchange the service area of which contains the mobile terminal. In the example in FIG. 1, when a mobile terminal 10 becomes present in the service area of an exchange 31, it registers its location via the exchange 31. In this case, the exchange 31 downloads the subscriber profile of the mobile terminal 10 from a home memory station 20 in order to obtain information on the mobile terminal 10. The subscriber profile may be personal information, locational information, service information, or the like.
FIGS. 2 and 3 are diagrams illustrating an example of a process of changing a subscriber profile in prior art. When the mobile terminal 10 transmits a request to change its subscriber profile to the exchange 31 (FIG. 2(a)), the exchange 31 transmits the change request to the home memory station 20 (FIG. 2 and FIG. 3(b)). Upon receiving the change request, the home memory station 20 change the subscriber profile of the mobile terminal 10 on the basis of the request ((c)). Then, the home memory station 20 transmits a change request response to the exchange 31((d)). The exchange 31 transmits the received change request response to the mobile terminal 10((e)). Also, the home memory station 20 transmits the changed subscriber profile to the exchange 31((f)). The exchange 31 changes (updates) a subscriber profile of the mobile terminal 10 retained thereby to the received one ((g)). After the change, the exchange 31 responds to the home memory station 20 by notifying it that the change process has been completed at the exchange (the exchange 31) whose service area has the mobile station 10((h)).
With this method, the subscriber profile in the home memory station 20 is changed and then the subscriber profile in the exchange 31 is changed, so that two round trips of inter-station signals are required between the home memory station 20 and the exchange 30.
This process is used partly because if the mobile terminal 10 moves to the service area of a new exchange, the home memory station 20 must transmit its subscriber profile to this new exchange, that is, the home memory station 20 must have the latest information.
FIGS. 4 and 5 show an example of a process executed in prior art if the change of the location registration is requested after the mobile terminal has moved to the service area of a different exchange. It is assumed that the mobile terminal 10, which shifts from the service area of the exchange 31 to the service area of an exchange 32, transmits a location registration change request to the exchange 32, which is the new exchange whose service area has the mobile terminal 10. The exchange 32 transmits this location registration request to the home memory station 20 (FIGS. 4 and 5(a)). Upon receiving the request, the home memory station 20 transmits a subscriber profile deletion request to the exchange 31, which is the old exchange whose service area had the mobile terminal 10((b)). Upon receiving the deletion request, the exchange 31 deletes its subscriber profile ((c)), and transmits a deletion completion response to the home memory station 20((d)). Upon receiving this response, the home memory station 20 changes its subscriber profile on the basis of the location registration request ((e)), and inputs the changed subscriber profile to the exchange 32((f)). Subsequently, a change process completion response is transmitted between the exchange 32 and the home memory station 20((g) and (h)).
Thus, in the prior art, when the subscriber profile is to be changed, a large number of signals are transmitted and received between the home memory station and the exchange.